1. Field of the Invention
The present invention relates to the field of water control valves. More particularly it concerns an improved float operated valve which permits water to trickle at a low flow rate into a tank when the water level is only slightly dropped below a selected level, but when the level is dropped more than a selected amount the valve opens farther to permit a high flow rate of water. The improved valve particularly concerns an easily serviceable, removable seat insert and an anti-syphon orifice that prevents reverse fluid flow.
2. Description of Prior Art
In the prior art as represented by my previous U.S. Pat. No. 4,298,022, entitled Energy Saver Control for Outdoor Water Heater, a float valve was utilized for opening or initiating a flow of water into an outdoor tank. Means were provided for restricting the flow into the tank, so that in cold weather, particularly, a small trickle of flow is provided to maintain a turbulent surface of the water in the tank so as to minimize freezing. Thus, as the water level was lowered in the tank, water flow was limited by appropriate means such as a needle valve, or an orifice, so as to flow at a minimum rate consistent with maintaining a clear water surface. However, if it should be desired to fill the tank rapidly, then a manual operation was required, to open the needle valve or remove the orifice, in order to get a much higher flow rate. My previous U.S. Pat. No. 4,298,022, entitled Low-High Flow Rate Valve, disclosed a valve that was adapted to supply water at either a low or high flow rate as desired. This invention was designed to provide both of these features, that is a low-rate of flow or a high-rate of flow, depending on the specific level of liquid in the tank, and this was done with one float-operated valve, whereas in my other patent, two floats and two float operated valves were required to accomplish this feat. The teachings of both of my prior patents, U.S. Pat. No. 4,298,022 and 4,352,371, are hereby expressly incorporated by reference herein.
While these systems work well for their intended function, experience has shown that maintenance operations can be difficult for these devices. In particular, the inner seat for the diaphragm was subject to tremendous stresses during use and as a result, it often required replacement prior to other portions of the diaphragm and valve. However, seat repair or replacement required removal of the entire valve and disassemble. This was an arduous, time-consuming task.
Further, in rare circumstances and under extreme operating conditions, the valves could become subject to a vacuum that caused negative flow pressure which could siphon liquids from the associated reservoir back through the valve. Naturally, this is undesirable and must necessarily be prevented.
An interesting device is shown in U.S. Pat. No. 4,566,484, wherein a liquid level controlling apparatus is described. However, no provision has been made for prevention of reverse fluid flow in this device. Further, the device would be difficult to surface since it is installed and operates under the service of the water.
U.S. Pat. No. 3,386,462 shows a differential pressure controlled system for regulating the level of liquid in a storage tank. The flow of liquid from a pressurized source is conducted to the storage tank at a regulated flow rate through a flow control valve when the inlet tank pressure is below the adjusted value. In this patent, my invention worked well for its intended purpose but it was also difficult to service and did not include an anti-syphon feature.
U.S. Pat. Nos. 3,447,569, 5,150,732, 4,316,480, 3,211,171 and 3,100,083 disclose pressure type valves of general relevance. These valves are generally directed to liquid level control and generally employ one or more diaphragms that are typically controlled by a pressure arrangement. The pressure is often supplied externally.
U.S. Pat. Nos. 3,760,839, 3,773,063, 2,986,155, 3,158,173 and 4,709,721 concern float valves associated with toilets and the like. As such, these valves are of general relevance since they tend to involve a single flow rate and are typically concerned with noise factors and the like.
U.S. Pat. Nos. 5,082,017 and 5,228,479 both describe valves with anti-siphon or back-flow prevention features. The former is designed for a toilet and comprises a valve having an imperfect seal that leaks air during vacuum conditions. The later describes a complex valve with springs and several chambers that may be installed to prevent contamination of a fluid source by insuring drainage of a sill cock.
U.S. Pat. No. 3,242,940 shows a liquid flow control valve for toilet flush tanks. The valve uses an integral nipple-like tube 9 against which diaphragm 19 seats. However, the tube 9 appears to be integrally secured to the stand pipe 22. Furthermore, the tube 9 does not appear to be narrow enough to fit within the openings provided in seating washer 7. Thus, it is not believed that tube 9 can be easily replaced in the flow control valve.
U.S. Pat. No. 2,971,525 shows a float operated valve that is interesting. The valve has a seat fitting 3 atop tube 2 against which the membrane valve seat element 21 mates when membrane 13 is depressed. The seat fitting 3 appears in FIG. 3 to be threaded and removable. However, during normal operation, the water level (as indicated by dashed line A in FIG. 1) would affect maintenance operations involving the removal of seat fitting 3. When fitting 3 is removed, the outer tube 4 apparently would rise off of shoulder 5 and become unaligned therewith. Of course, this is undesirable and would require additional diligence during maintenance operations to insure that the valve was properly reassembled. It is believed that such diligence would necessarily require additional training and/or time during maintenance. Since it is further believed that the seat fitting 3 is critical to the structural stability for the valve, removal of the fitting would inherently weaken the stability of the valve undesirably. Also, the flanges encircling seat 3 would apparently hamper access thereto. The flanges could also apparently interfere with seat sealing in some circumstances. In particular the seat must depress when seating instead of forming a seal in a natural plane.
Thus, there is a need for an easily serviceable, anti-siphon, low-high flow rate valve. An ideal device will overcome problems associated with the known art while maintaining simplistic construction.